Ledger to masonry wall
A wood or steel ledger bolted to the face of a grouted concrete masonry wall, carrying a floor or roof: the cast-in headed anchor bolts by TMS 402-22 strength design (gravity shear, the tension from the ledger's eccentricity, and the wall anchorage when it is routed through the ledger), the ledger itself, the prohibition of cross-grain bending of wood ledgers, and the wall anchorage forces of ASCE 7-22 12.11.2.1 and 1.4.4. US and metric units.
Edition. TMS 402-22 is not on hand: the bolts use the shared anchor library, as the masonry anchor type does (402-13 / 402-16 text with the 2022 changes from the TMS handouts, marked to confirm). The wood ledger uses NDS 2024 (on hand), ASCE 7-22 12.11.2 and 1.4.4 are read in the library copy, and CMHA TEK 12-03C (on hand) gives the lever arm. The method switch is hidden: strength design (LRFD) only.
Inputs of the ledger #
- Ledger: sawn lumber (species, grade, size) or a steel angle (legs, thickness, Fy, Fu). For wood, the dowel bearing strength of the grouted masonry Fem: no published value exists; 3 f′m ≤ 7,500 psi by analogy with concrete (AWC TR12 Table A1) is prefilled, your call.
- Bolts: diameter, steel, embedment to the bearing surface of the head, spacing along the ledger, the bolt's distance below the top of the ledger, and the lever arm factor for the eccentricity (5/6 of the bolt-to-bottom-of-ledger distance, TEK 12-03C).
- Wall: concrete masonry thickness (grouted at the bolts), f′m, grout, and the distances from the bolt row to the masonry edges below (the shear acts toward it) and above.
- Loads: dead, live, roof live or snow per foot on the ledger, the load line from the wall face (the hangers' bearing line), and the NDS live load λ.
- Wall anchorage: through separate ties (the ledger carries gravity only) or through the ledger bolts; the seismic design category, SDS, Ie, the flexible diaphragm span, the wall weight and height tributary to the ledger line, the wind on the wall; with the anchorage through the bolts, the factor of ASCE 7-22 14.4.5 on seismic forces not governed by steel (on, 2.0, as in the masonry anchor type).
Auto-design varies the bolt spacing and diameter and the ledger size. Objective: the fewest and smallest bolts, then the smallest ledger.
Checks performed #
| Check | Basis |
|---|---|
| No cross-grain bending of a wood ledger for wall anchorage, SDC C to F | ASCE 7-22 12.11.2.2.3 |
| Bolt tension, shear, interaction | TMS 402-22 9.1.6.3: breakout on Apt (the row's cones shared, cut by the edges), steel from fu, crushing, pryout, breakout toward the edge below; exponent 5/3 |
| Embedment, grout around the head, clear distance | 6.3.1, 6.3.6 |
| Bolt bearing in the wood ledger | NDS 2024 Table 12.3.1A yield limits, Fe⊥ of the ledger, Fem of the masonry; Z′ = Z KF φz λ |
| Ledger bending and shear between bolts | NDS 2024 3.3, 3.4 (simple span between bolts) |
| Edge distances in the ledger | NDS 2024 Table 12.5.1C: 4D to the loaded edge, 1.5D to the unloaded edge |
| Steel angle: bearing at the hole, the outstanding leg | AISC 360-22 J3.10, F11.1 |
| Wall anchorage | ASCE 7-22 12.11.2.1, 1.4.4; reported for separate ties, added to the bolts when routed through the ledger |
The drawing is a section through the wall, the ledger and one bolt.
Limitations #
- One row of cast-in headed bolts in grouted concrete masonry. Post-installed anchors, bent bars, hollow masonry and brick are not covered.
- Joist hangers, continuous ties and subdiaphragms (12.11.2.2.1), the wall out of plane and ledger splices are not designed.
- The ledger spans simply between bolts (conservative); its own end distances at splices are not checked.
- Strength design only.
Verification examples #
Verification status: 11 values compared in 4 examples (1 published, 3 hand calculations from the cited equations): 11 within tolerance, 0 recorded deviations. Thin: only 1 published example. Code basis: not yet recorded for this module.
Published: the tension from the eccentric load in CMHA TEK 12-03C's strength design example (2,688 lb for two bolts). TEK 12-03C's anchor strengths follow TMS 402-13 and differ from the current equations, so they are not compared. The rest are hand calculations from NDS 2024, TMS 402 and ASCE 7-22.